Klaviyo
Shopify
Mailchimp
Omnisend
HubSpot
SendGrid
Brevo
Sendlane
Customer.io
Mailgun
Amazon SES
Ongage
ExpertSender
Zoho Mail
GMX Mail
Email Deliverability
Tips
The complete guide to
reaching the inbox.
authentication, reputation, warm-up and monitoring.
- 1
Share email provider
Avoid using AWS SES and Mailgun for cold emailing, as they are designed for opt-in emails. Instead, consider using Google, Microsoft, or Zoho
- 2
Rotate inboxes & Use several domains
To increase sending limits, utilize multiple inboxes by setting up 4-5 inboxes per domain and leveraging an unlimited number of domains. It’s essential to regularly refresh domains that exhibit low performance to maintain optimal efficiency. We have created a mailbox calculator that allows you to determine the number of mailboxes and domains needed for your sending requirements
- 3
Email authentication
Ensure that your SPF/DKIM/DMARC is in place. These digital signatures confirm that you had permission to send the email. Without them, the receiving server may assume you are a fraud
- 4
Warm-up mailboxes
Warm up your email campaign for 2 weeks with Warmy, which automatically adjusts the number of warm-up emails and determines the optimal reply rate. After this initial phase, aim for a steady increase in the number of emails per day, while Warmy’s AI engine continues to set the ideal reply rate each day throughout your campaign
- 5
Boost email deliverability
To maintain high deliverability, avoid sending emails to your ‘Do Not Contact’ list, as being reported as spam can damage your reputation. Maintain consistent sending patterns by gradually increasing and decreasing your email volume, and always use email validation tools to check your recipient lists and keep your database clean. Prioritize aiming for a reply rather than a click. Respond to all unsubscribe requests to confirm that you will no longer contact them
- 6
Personalisation & Unique content
Unique emails are more likely to be delivered, and personalization can positively impact open and reply rates, thereby enhancing deliverability. Equally important is your subject line, as it’s the first thing recipients see and significantly influences open rates. Utilize Spintax to make each email unique and conduct A/B testing to optimize performance
- 7
Use plain text
Plain text emails generally have a higher delivery rate compared to HTML emails. However, even when composing in a standard email editor, the email will still be sent as HTML. To improve delivery rates, try to use more text rather than excessive HTML in your emails
- 8
SPAM words
Refrain from using spam-triggering words whenever possible, and review each email before adding it to your sequence. For assistance, check out our Free Template Checker
- 9
Managing email content for optimal deliverability
Minimize the use of images, including in your email signature, and consider adding them only in your second or third email if necessary. Unsubscribe links can lower deliverability rates but, on the other hand, are mandatory for bulk senders. They help reduce the risk of your emails being marked as spam. Additionally, limit the use of links to one per email, including those in signature
- 10
Email sending limits & Consistency
If you are sending from an inbox, limit your daily emails to 50-100 and distribute them evenly throughout the day. Maintain consistent sending patterns by gradually increasing and decreasing your email volume
Email Deliverability Checklist
Work through this list at each stage of a sending programme.
Before launching
- SPF, DKIM and DMARC published and passing
- Custom tracking and sending domain aligned
- Domain and IP warm-up scheduled
- Seed list inbox placement baseline recorded
Before every campaign
- List verified and suppressions applied
- Template checked for spam signals and broken links
- Volume within the planned ramp
- Unsubscribe and list headers present
After sending
- Bounce and complaint rates reviewed
- Inbox versus spam placement compared
- Engagement by segment inspected
- Hard bounces suppressed immediately
Weekly and monthly
- Blocklist checks for domain and IP
- Google Postmaster reputation trend
- Authentication pass rates reviewed
- Monthly reputation and list-hygiene review
Why Are My Emails Going to Spam?
Match the symptom to the signal, then take the recommended action.
| Possible cause | What to check | Recommended action |
|---|---|---|
| Authentication failure | SPF, DKIM and DMARC results | Correct DNS records and alignment |
| Poor reputation | Domain and IP reputation | Reduce volume and improve engagement |
| High bounce rate | Invalid-address percentage | Verify and clean the list |
| Sudden volume increase | Daily sending history | Scale gradually |
| Spam complaints | Complaint and unsubscribe data | Improve targeting and consent |
| Blocklist entry | Domain and IP blocklists | Identify the cause and remediate it |
| Risky content | Links, HTML and formatting | Test the template before sending |
How to Measure Email Deliverability
Open rates alone cannot diagnose deliverability. Track these together.
- Inbox placement rate
- Spam placement rate
- Bounce rate
- Complaint rate
- Unsubscribe rate
- Engagement trends over time
- Domain and IP reputation
- Authentication pass rates
How Warmy Helps Improve Email Deliverability
Every signal above is something Warmy can measure, improve or monitor for you.
Automated domain and IP warm-up
Adeline AI sets the pace, volume and reply rate for every mailbox, every day.
Inbox placement testing
Seed tests across every major provider show exactly where your messages land.
SPF, DKIM and DMARC checks
Authentication is validated continuously, not once at setup.
Blacklist monitoring
Domain and IP listings are detected and reported as they happen.
Google Postmaster integration
Gmail reputation data pulled into one dashboard alongside everything else.
Template checking
Spot spam triggers, broken links and risky HTML before you send.
“Deliverability is never fixed once. It is a reputation you maintain every single day, with consistent volume, clean data and honest content.”
Frequently AskedQuestions
What is email deliverability?
Email deliverability is the ability of your messages to reach the recipient’s inbox rather than being rejected or filtered into spam. It is determined by domain and IP reputation, authentication, sending patterns, list quality and recipient engagement, all evaluated by the mailbox provider at the moment of delivery.